1 /*
2 * Microsoft Video-1 Decoder
3 * Copyright (C) 2003 The FFmpeg project
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file
24 * Microsoft Video-1 Decoder by Mike Melanson (melanson@pcisys.net)
25 * For more information about the MS Video-1 format, visit:
26 * http://www.pcisys.net/~melanson/codecs/
27 */
28
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <string.h>
32
33 #include "libavutil/internal.h"
34 #include "libavutil/intreadwrite.h"
35 #include "avcodec.h"
36 #include "codec_internal.h"
37 #include "decode.h"
38 #include "internal.h"
39
40 #define PALETTE_COUNT 256
41 #define CHECK_STREAM_PTR(n) \
42 if ((stream_ptr + n) > s->size ) { \
43 av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
44 stream_ptr + n, s->size); \
45 return; \
46 }
47
48 typedef struct Msvideo1Context {
49
50 AVCodecContext *avctx;
51 AVFrame *frame;
52
53 const unsigned char *buf;
54 int size;
55
56 int mode_8bit; /* if it's not 8-bit, it's 16-bit */
57
58 uint32_t pal[256];
59 } Msvideo1Context;
60
msvideo1_decode_init(AVCodecContext *avctx)61 static av_cold int msvideo1_decode_init(AVCodecContext *avctx)
62 {
63 Msvideo1Context *s = avctx->priv_data;
64
65 s->avctx = avctx;
66
67 if (avctx->width < 4 || avctx->height < 4)
68 return AVERROR_INVALIDDATA;
69
70 /* figure out the colorspace based on the presence of a palette */
71 if (s->avctx->bits_per_coded_sample == 8) {
72 s->mode_8bit = 1;
73 avctx->pix_fmt = AV_PIX_FMT_PAL8;
74 if (avctx->extradata_size >= AVPALETTE_SIZE)
75 memcpy(s->pal, avctx->extradata, AVPALETTE_SIZE);
76 } else {
77 s->mode_8bit = 0;
78 avctx->pix_fmt = AV_PIX_FMT_RGB555;
79 }
80
81 s->frame = av_frame_alloc();
82 if (!s->frame)
83 return AVERROR(ENOMEM);
84
85 return 0;
86 }
87
msvideo1_decode_8bit(Msvideo1Context *s)88 static void msvideo1_decode_8bit(Msvideo1Context *s)
89 {
90 int block_ptr, pixel_ptr;
91 int total_blocks;
92 int pixel_x, pixel_y; /* pixel width and height iterators */
93 int block_x, block_y; /* block width and height iterators */
94 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
95 int block_inc;
96 int row_dec;
97
98 /* decoding parameters */
99 int stream_ptr;
100 unsigned char byte_a, byte_b;
101 unsigned short flags;
102 int skip_blocks;
103 unsigned char colors[8];
104 unsigned char *pixels = s->frame->data[0];
105 int stride = s->frame->linesize[0];
106
107 stream_ptr = 0;
108 skip_blocks = 0;
109 blocks_wide = s->avctx->width / 4;
110 blocks_high = s->avctx->height / 4;
111 total_blocks = blocks_wide * blocks_high;
112 block_inc = 4;
113 row_dec = stride + 4;
114
115 for (block_y = blocks_high; block_y > 0; block_y--) {
116 block_ptr = ((block_y * 4) - 1) * stride;
117 for (block_x = blocks_wide; block_x > 0; block_x--) {
118 /* check if this block should be skipped */
119 if (skip_blocks) {
120 block_ptr += block_inc;
121 skip_blocks--;
122 total_blocks--;
123 continue;
124 }
125
126 pixel_ptr = block_ptr;
127
128 /* get the next two bytes in the encoded data stream */
129 CHECK_STREAM_PTR(2);
130 byte_a = s->buf[stream_ptr++];
131 byte_b = s->buf[stream_ptr++];
132
133 /* check if the decode is finished */
134 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
135 return;
136 else if ((byte_b & 0xFC) == 0x84) {
137 /* skip code, but don't count the current block */
138 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
139 } else if (byte_b < 0x80) {
140 /* 2-color encoding */
141 flags = (byte_b << 8) | byte_a;
142
143 CHECK_STREAM_PTR(2);
144 colors[0] = s->buf[stream_ptr++];
145 colors[1] = s->buf[stream_ptr++];
146
147 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
148 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
149 pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
150 pixel_ptr -= row_dec;
151 }
152 } else if (byte_b >= 0x90) {
153 /* 8-color encoding */
154 flags = (byte_b << 8) | byte_a;
155
156 CHECK_STREAM_PTR(8);
157 memcpy(colors, &s->buf[stream_ptr], 8);
158 stream_ptr += 8;
159
160 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
161 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
162 pixels[pixel_ptr++] =
163 colors[((pixel_y & 0x2) << 1) +
164 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
165 pixel_ptr -= row_dec;
166 }
167 } else {
168 /* 1-color encoding */
169 colors[0] = byte_a;
170
171 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
172 for (pixel_x = 0; pixel_x < 4; pixel_x++)
173 pixels[pixel_ptr++] = colors[0];
174 pixel_ptr -= row_dec;
175 }
176 }
177
178 block_ptr += block_inc;
179 total_blocks--;
180 }
181 }
182
183 /* make the palette available on the way out */
184 if (s->avctx->pix_fmt == AV_PIX_FMT_PAL8)
185 memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);
186 }
187
msvideo1_decode_16bit(Msvideo1Context *s)188 static void msvideo1_decode_16bit(Msvideo1Context *s)
189 {
190 int block_ptr, pixel_ptr;
191 int total_blocks;
192 int pixel_x, pixel_y; /* pixel width and height iterators */
193 int block_x, block_y; /* block width and height iterators */
194 int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
195 int block_inc;
196 int row_dec;
197
198 /* decoding parameters */
199 int stream_ptr;
200 unsigned char byte_a, byte_b;
201 unsigned short flags;
202 int skip_blocks;
203 unsigned short colors[8];
204 unsigned short *pixels = (unsigned short *)s->frame->data[0];
205 int stride = s->frame->linesize[0] / 2;
206
207 stream_ptr = 0;
208 skip_blocks = 0;
209 blocks_wide = s->avctx->width / 4;
210 blocks_high = s->avctx->height / 4;
211 total_blocks = blocks_wide * blocks_high;
212 block_inc = 4;
213 row_dec = stride + 4;
214
215 for (block_y = blocks_high; block_y > 0; block_y--) {
216 block_ptr = ((block_y * 4) - 1) * stride;
217 for (block_x = blocks_wide; block_x > 0; block_x--) {
218 /* check if this block should be skipped */
219 if (skip_blocks) {
220 block_ptr += block_inc;
221 skip_blocks--;
222 total_blocks--;
223 continue;
224 }
225
226 pixel_ptr = block_ptr;
227
228 /* get the next two bytes in the encoded data stream */
229 CHECK_STREAM_PTR(2);
230 byte_a = s->buf[stream_ptr++];
231 byte_b = s->buf[stream_ptr++];
232
233 /* check if the decode is finished */
234 if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
235 return;
236 } else if ((byte_b & 0xFC) == 0x84) {
237 /* skip code, but don't count the current block */
238 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
239 } else if (byte_b < 0x80) {
240 /* 2- or 8-color encoding modes */
241 flags = (byte_b << 8) | byte_a;
242
243 CHECK_STREAM_PTR(4);
244 colors[0] = AV_RL16(&s->buf[stream_ptr]);
245 stream_ptr += 2;
246 colors[1] = AV_RL16(&s->buf[stream_ptr]);
247 stream_ptr += 2;
248
249 if (colors[0] & 0x8000) {
250 /* 8-color encoding */
251 CHECK_STREAM_PTR(12);
252 colors[2] = AV_RL16(&s->buf[stream_ptr]);
253 stream_ptr += 2;
254 colors[3] = AV_RL16(&s->buf[stream_ptr]);
255 stream_ptr += 2;
256 colors[4] = AV_RL16(&s->buf[stream_ptr]);
257 stream_ptr += 2;
258 colors[5] = AV_RL16(&s->buf[stream_ptr]);
259 stream_ptr += 2;
260 colors[6] = AV_RL16(&s->buf[stream_ptr]);
261 stream_ptr += 2;
262 colors[7] = AV_RL16(&s->buf[stream_ptr]);
263 stream_ptr += 2;
264
265 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
266 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
267 pixels[pixel_ptr++] =
268 colors[((pixel_y & 0x2) << 1) +
269 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
270 pixel_ptr -= row_dec;
271 }
272 } else {
273 /* 2-color encoding */
274 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
275 for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
276 pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
277 pixel_ptr -= row_dec;
278 }
279 }
280 } else {
281 /* otherwise, it's a 1-color block */
282 colors[0] = (byte_b << 8) | byte_a;
283
284 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
285 for (pixel_x = 0; pixel_x < 4; pixel_x++)
286 pixels[pixel_ptr++] = colors[0];
287 pixel_ptr -= row_dec;
288 }
289 }
290
291 block_ptr += block_inc;
292 total_blocks--;
293 }
294 }
295 }
296
msvideo1_decode_frame(AVCodecContext *avctx, AVFrame *rframe, int *got_frame, AVPacket *avpkt)297 static int msvideo1_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
298 int *got_frame, AVPacket *avpkt)
299 {
300 const uint8_t *buf = avpkt->data;
301 int buf_size = avpkt->size;
302 Msvideo1Context *s = avctx->priv_data;
303 int ret;
304
305 s->buf = buf;
306 s->size = buf_size;
307
308 // Discard frame if its smaller than the minimum frame size
309 if (buf_size < (avctx->width/4) * (avctx->height/4) / 512) {
310 av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
311 return AVERROR_INVALIDDATA;
312 }
313
314 if ((ret = ff_reget_buffer(avctx, s->frame, 0)) < 0)
315 return ret;
316
317 if (s->mode_8bit) {
318 s->frame->palette_has_changed = ff_copy_palette(s->pal, avpkt, avctx);
319 }
320
321 if (s->mode_8bit)
322 msvideo1_decode_8bit(s);
323 else
324 msvideo1_decode_16bit(s);
325
326 if ((ret = av_frame_ref(rframe, s->frame)) < 0)
327 return ret;
328
329 *got_frame = 1;
330
331 /* report that the buffer was completely consumed */
332 return buf_size;
333 }
334
msvideo1_decode_end(AVCodecContext *avctx)335 static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
336 {
337 Msvideo1Context *s = avctx->priv_data;
338
339 av_frame_free(&s->frame);
340
341 return 0;
342 }
343
344 const FFCodec ff_msvideo1_decoder = {
345 .p.name = "msvideo1",
346 .p.long_name = NULL_IF_CONFIG_SMALL("Microsoft Video 1"),
347 .p.type = AVMEDIA_TYPE_VIDEO,
348 .p.id = AV_CODEC_ID_MSVIDEO1,
349 .priv_data_size = sizeof(Msvideo1Context),
350 .init = msvideo1_decode_init,
351 .close = msvideo1_decode_end,
352 FF_CODEC_DECODE_CB(msvideo1_decode_frame),
353 .p.capabilities = AV_CODEC_CAP_DR1,
354 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
355 };
356